A number of baculoviruses are being considered for use in pest management programs. The Baculovirus genome is capable of coding for well over 100 polypeptides. Recent advances in transcriptional and translational mapping have provided a number of methods for understanding the organization and expression of such complex genomes. This approach involves using a specific clones restriction fragment to selectively purify (by hybridization) the mRNAs transcribed from that fragment. The selected mRNAs can then be eluted from the DNA and separated on methyl mercury agarose gels to determine the number and size of the mRNAs derived from the cloned DNA fragments. The different mRNAs can be purified from the gels and the mRNA products can be characterized by the translation of the purified mRNA. In addition, these specific mRNAs can be labeled and hybridized to mapped restriction endonuclease generted subfragments of the cloned DNA to determine their exact location on the original fragment. We propose to begin this procedure with the Xho 1-J cloned fragment which contains the polyhedrin gene. We have cloned this fragment into two diffeerent plasmids. In the proposed research, we wish to prepare a translational map of this DNA fragment and subsequently move outward into the fragments flanking this region. The cloned fragment is 3.4 x 10 to the sixth (about 5000 bp) and contains enough information to code for seven proteins the size of polyhedrin. In order to understand the organization and function of this region of the virus genome we will investigate four areas including: 1) genome organization and expression; 2) nature of the Baculovirus genes; 3) the function of the gene products; 4) the nucleotide sequence of a Baculovirus gene (polyhedrin). Because the use of baculoviruses as a part of pest management is rapidly approaching, there is a need to understand the nature and function of the Baculovirus genome. The purpose of this research is to provide this information so that an intelligent evaluation can be made of the possible effects of virus exposure during virus production and its application to the environment.